Hard-rolling rollers generally have the shape of a low truncated cone. The base area of these truncated cones is very rounded at the edges, sometimes with different radiuses, which results in a nearly torus-shaped body. Hard-rolling rollers of the designated type are known, for example, from DE 102 30 526 A1, see FIG. 2. But hard-rolling rollers of the designated type are also shown in WO 2005/023488 A1, see FIG. 10 to FIG. 12. The hard-rolling rollers mentioned are used interchangeably in the deep rolling tools and are loosely and rotatably guided in the cages. A cage of the designated type is known, for example, from DE 100 42 425 B4. When using the above-mentioned hard-rolling rollers in the deep rolling tools, it may happen that the hard-rolling rollers are clamped in an inverted position between the cages. The consequences are premature wear of the cage and the hard-rolling rollers and an incorrectly machined crankshaft.
Hence the resulting task for the present invention is to design a hard-rolling roller in such a way that it is always mounted in the prescribed, i.e. correct, mounting position in the deep rolling tool.
According to the invention, this task is solved by the fact that a cylindrical body rises on the upper end surface of one of the two central bodies.
From U.S. Pat. No. 6,393,885 B1, hard-rolling rollers having different shapes are known in addition to the hard-rolling rollers of the type mentioned (see FIG. 3, FIG. 5a and FIG. 5b). Such hard-rolling rollers have a torus-shaped base body for deep rolling of radiuses or recesses which limit the bearing trunnions on the crankshafts on both sides, and two at least approximately truncated cone-shaped central bodies which rise on both sides of the base body, see FIG. 6 to FIG. 11. However, the known hard-rolling rollers are not intended to prevent improper installation. The design rather results from the fact that a broadened support surface at the guide roller has been created for the torus-shaped base body which has to do most of the work at deep rolling. In this way, the deep rolling force no longer acts directly on the base body on the hard-rolling roller, but on the at least approximately truncated cone-shaped central bodies rising on either side of the base body; see FIG. 6.